DIN 921 Slotted Pan Head Screws with Large Head
DIN 921 slotted pan head screws with enlarged head, M1 to M10 — the oversized pan head that spreads clamp load over a bigger bearing circle without a washer — with the full collected 12-size table: enlarged head limits and slot geometry.
Last updated: 2026-11
Specifications
DIN 921 is the pan head screw enlarged at the head: same thread, same slot, but a head diameter roughly 1.5–2× the standard pan series — the collected table prints d k 12 at M4 against DIN 923’s 8.5, and 30 at M10 against 20. The enlarged bearing circle spreads the same clamp load over more area, so soft or finished clamped faces are supported without a separate washer, and the bigger slot runs deeper for a firmer blade fit at the same thread size. That combination — washer function built into the head plus better drive depth — is why the large-head form shows up on sheet-metal assemblies, plastics and painted faces where a washer would be one more part to handle. The table runs M1 to M10 and tabulates per size: pitch P, runout a max, head diameter d k (max=nominal / min), head height k (Nominal / max / min), slot width n (Nominal / max / min), slot depth t (max / min), the c chamfer and fillet r limits. Compare DIN 923 for the standard head and DIN 920 for the small-head series on this site. Materials, property classes and finishes are not printed by the collected specification and follow the drawing callout.
| Standard | DIN 921 — slotted pan head screws with large head (enlarged bearing circle) |
|---|---|
| Series | M1 – M10 (12 sizes tabulated) |
| Tabulated geometry | Per size: pitch P, runout a max, head diameter d k (max=nominal / min), head height k (Nominal / max / min), slot width n (Nominal / max / min), slot depth t (max / min), chamfer c (≈), fillet r max |
| Dimensions at M4 | Head d k max=nominal 12 / min 11.57 (vs 8.5 for DIN 923); head height k nominal 2.4; slot n nominal 1 (1.06–1.2); slot depth t max 1.5 / min 1.2; chamfer c ≈ 0.6 |
| Dimensions at M10 | Head d k max=nominal 30 / min 29.48 (vs 20 for DIN 923); head height k nominal 4.6; slot n nominal 2.5; slot depth t max 2.8 / min 2.3; chamfer c ≈ 1.1 |
| Head / drive form | Enlarged pan head — washer-style bearing circle with slotted drive |
| Materials / strength | Not tabulated by the collected specification — per RFQ (property class and finish per drawing callout) |
Materials
- Material, property class and finish specified per RFQ — the collected specification table covers geometry only
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (DIN 921 Slotted Pan Head Screws with Large Head) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Can a large pan head really replace a flat washer?
Mechanically, most of the time it can — that is what the d k column is for. At M4 the enlarged head bears on a 12 mm circle against the standard head’s 8.5 mm, so bearing pressure on the clamped face drops to roughly half, which is exactly the service a thin flat washer performs. Where the substitution holds: soft clamped materials, painted or anodised faces, thin sheet — anywhere the goal is spreading load and hiding rotation marks. Where it does not: when the washer must span an oversize or slotted hole, provide insulation, or be a separate grade/finish material from the screw, a large head cannot do the washer’s other jobs. Note also the profile cost — the large head is taller (k 2.4 vs 1.6 at M4 in the collected tables), so check stack height before switching a drawing over.
What is the MOQ and lead time for these screws?
Minimum order quantity is 10,000 pieces per item. Stocked sizes ship in 3–7 days; non-stock diameters, lengths or finishes are quoted with a confirmed schedule. Common sizes in this designation are widely stocked — confirm the exact schedule against quantity and size mix at quotation.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support